Older copyright updates

test/filter_test.exs

test/http_test.exs

test/plugs/basic_auth_decoder_plug_test.exs

test/plugs/ensure_authenticated_plug_test.exs

test/plugs/ensure_user_key_plug_test.exs

test/plugs/session_authentication_plug_test.exs

test/plugs/set_user_session_id_plug_test.exs

test/plugs/user_fetcher_plug_test.exs

test/support/websocket_client.ex

test/tasks/uploads_test.exs

test/xml_builder_test.exs